xref: /openbsd/sys/uvm/uvm_mmap.c (revision 3bef86f7)
1 /*	$OpenBSD: uvm_mmap.c,v 1.185 2024/01/19 21:20:35 deraadt Exp $	*/
2 /*	$NetBSD: uvm_mmap.c,v 1.49 2001/02/18 21:19:08 chs Exp $	*/
3 
4 /*
5  * Copyright (c) 1997 Charles D. Cranor and Washington University.
6  * Copyright (c) 1991, 1993 The Regents of the University of California.
7  * Copyright (c) 1988 University of Utah.
8  *
9  * All rights reserved.
10  *
11  * This code is derived from software contributed to Berkeley by
12  * the Systems Programming Group of the University of Utah Computer
13  * Science Department.
14  *
15  * Redistribution and use in source and binary forms, with or without
16  * modification, are permitted provided that the following conditions
17  * are met:
18  * 1. Redistributions of source code must retain the above copyright
19  *    notice, this list of conditions and the following disclaimer.
20  * 2. Redistributions in binary form must reproduce the above copyright
21  *    notice, this list of conditions and the following disclaimer in the
22  *    documentation and/or other materials provided with the distribution.
23  * 3. Neither the name of the University nor the names of its contributors
24  *    may be used to endorse or promote products derived from this software
25  *    without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37  * SUCH DAMAGE.
38  *
39  * from: Utah $Hdr: vm_mmap.c 1.6 91/10/21$
40  *      @(#)vm_mmap.c   8.5 (Berkeley) 5/19/94
41  * from: Id: uvm_mmap.c,v 1.1.2.14 1998/01/05 21:04:26 chuck Exp
42  */
43 
44 /*
45  * uvm_mmap.c: system call interface into VM system, plus kernel vm_mmap
46  * function.
47  */
48 #include <sys/param.h>
49 #include <sys/systm.h>
50 #include <sys/fcntl.h>
51 #include <sys/file.h>
52 #include <sys/filedesc.h>
53 #include <sys/resourcevar.h>
54 #include <sys/mman.h>
55 #include <sys/mount.h>
56 #include <sys/proc.h>
57 #include <sys/malloc.h>
58 #include <sys/vnode.h>
59 #include <sys/conf.h>
60 #include <sys/signalvar.h>
61 #include <sys/syslog.h>
62 #include <sys/stat.h>
63 #include <sys/specdev.h>
64 #include <sys/stdint.h>
65 #include <sys/pledge.h>
66 #include <sys/unistd.h>		/* for KBIND* */
67 #include <sys/user.h>
68 
69 #include <machine/exec.h>	/* for __LDPGSZ */
70 
71 #include <sys/syscall.h>
72 #include <sys/syscallargs.h>
73 
74 #include <uvm/uvm.h>
75 #include <uvm/uvm_device.h>
76 #include <uvm/uvm_vnode.h>
77 
78 int uvm_mmapanon(vm_map_t, vaddr_t *, vsize_t, vm_prot_t, vm_prot_t, int,
79     vsize_t, struct proc *);
80 int uvm_mmapfile(vm_map_t, vaddr_t *, vsize_t, vm_prot_t, vm_prot_t, int,
81     struct vnode *, voff_t, vsize_t, struct proc *);
82 
83 
84 /*
85  * Page align addr and size, returning EINVAL on wraparound.
86  */
87 #define ALIGN_ADDR(addr, size, pageoff)	do {				\
88 	pageoff = (addr & PAGE_MASK);					\
89 	if (pageoff != 0) {						\
90 		if (size > SIZE_MAX - pageoff)				\
91 			return EINVAL;	/* wraparound */	\
92 		addr -= pageoff;					\
93 		size += pageoff;					\
94 	}								\
95 	if (size != 0) {						\
96 		size = (vsize_t)round_page(size);			\
97 		if (size == 0)						\
98 			return EINVAL;	/* wraparound */	\
99 	}								\
100 } while (0)
101 
102 /*
103  * sys_mquery: provide mapping hints to applications that do fixed mappings
104  *
105  * flags: 0 or MAP_FIXED (MAP_FIXED - means that we insist on this addr and
106  *	don't care about PMAP_PREFER or such)
107  * addr: hint where we'd like to place the mapping.
108  * size: size of the mapping
109  * fd: fd of the file we want to map
110  * off: offset within the file
111  */
112 int
113 sys_mquery(struct proc *p, void *v, register_t *retval)
114 {
115 	struct sys_mquery_args /* {
116 		syscallarg(void *) addr;
117 		syscallarg(size_t) len;
118 		syscallarg(int) prot;
119 		syscallarg(int) flags;
120 		syscallarg(int) fd;
121 		syscallarg(off_t) pos;
122 	} */ *uap = v;
123 	struct file *fp;
124 	voff_t uoff;
125 	int error;
126 	vaddr_t vaddr;
127 	int flags = 0;
128 	vsize_t size;
129 	vm_prot_t prot;
130 	int fd;
131 
132 	vaddr = (vaddr_t) SCARG(uap, addr);
133 	prot = SCARG(uap, prot);
134 	size = (vsize_t) SCARG(uap, len);
135 	fd = SCARG(uap, fd);
136 
137 	if ((prot & PROT_MASK) != prot)
138 		return EINVAL;
139 
140 	if (SCARG(uap, flags) & MAP_FIXED)
141 		flags |= UVM_FLAG_FIXED;
142 
143 	if (fd >= 0) {
144 		if ((error = getvnode(p, fd, &fp)) != 0)
145 			return error;
146 		uoff = SCARG(uap, pos);
147 	} else {
148 		fp = NULL;
149 		uoff = UVM_UNKNOWN_OFFSET;
150 	}
151 
152 	if (vaddr == 0)
153 		vaddr = uvm_map_hint(p->p_vmspace, prot, VM_MIN_ADDRESS,
154 		    VM_MAXUSER_ADDRESS);
155 
156 	error = uvm_map_mquery(&p->p_vmspace->vm_map, &vaddr, size, uoff,
157 	    flags);
158 	if (error == 0)
159 		*retval = (register_t)(vaddr);
160 
161 	if (fp != NULL)
162 		FRELE(fp, p);
163 	return error;
164 }
165 
166 int	uvm_wxabort;
167 
168 /*
169  * W^X violations are only allowed on permitted filesystems.
170  */
171 static inline int
172 uvm_wxcheck(struct proc *p, char *call)
173 {
174 	struct process *pr = p->p_p;
175 	int wxallowed = (pr->ps_textvp->v_mount &&
176 	    (pr->ps_textvp->v_mount->mnt_flag & MNT_WXALLOWED));
177 
178 	if (wxallowed && (pr->ps_flags & PS_WXNEEDED))
179 		return 0;
180 
181 	if (uvm_wxabort) {
182 		KERNEL_LOCK();
183 		/* Report W^X failures */
184 		if (pr->ps_wxcounter++ == 0)
185 			log(LOG_NOTICE, "%s(%d): %s W^X violation\n",
186 			    pr->ps_comm, pr->ps_pid, call);
187 		/* Send uncatchable SIGABRT for coredump */
188 		sigexit(p, SIGABRT);
189 		KERNEL_UNLOCK();
190 	}
191 
192 	return ENOTSUP;
193 }
194 
195 /*
196  * sys_mmap: mmap system call.
197  *
198  * => file offset and address may not be page aligned
199  *    - if MAP_FIXED, offset and address must have remainder mod PAGE_SIZE
200  *    - if address isn't page aligned the mapping starts at trunc_page(addr)
201  *      and the return value is adjusted up by the page offset.
202  */
203 int
204 sys_mmap(struct proc *p, void *v, register_t *retval)
205 {
206 	struct sys_mmap_args /* {
207 		syscallarg(void *) addr;
208 		syscallarg(size_t) len;
209 		syscallarg(int) prot;
210 		syscallarg(int) flags;
211 		syscallarg(int) fd;
212 		syscallarg(off_t) pos;
213 	} */ *uap = v;
214 	vaddr_t addr;
215 	struct vattr va;
216 	off_t pos;
217 	vsize_t limit, pageoff, size;
218 	vm_prot_t prot, maxprot;
219 	int flags, fd;
220 	vaddr_t vm_min_address = VM_MIN_ADDRESS;
221 	struct filedesc *fdp = p->p_fd;
222 	struct file *fp = NULL;
223 	struct vnode *vp;
224 	int error;
225 
226 	/* first, extract syscall args from the uap. */
227 	addr = (vaddr_t) SCARG(uap, addr);
228 	size = (vsize_t) SCARG(uap, len);
229 	prot = SCARG(uap, prot);
230 	flags = SCARG(uap, flags);
231 	fd = SCARG(uap, fd);
232 	pos = SCARG(uap, pos);
233 
234 	/*
235 	 * Validate the flags.
236 	 */
237 	if ((prot & PROT_MASK) != prot)
238 		return EINVAL;
239 	if ((prot & (PROT_WRITE | PROT_EXEC)) == (PROT_WRITE | PROT_EXEC) &&
240 	    (error = uvm_wxcheck(p, "mmap")))
241 		return error;
242 
243 	if ((flags & MAP_FLAGMASK) != flags)
244 		return EINVAL;
245 	if ((flags & (MAP_SHARED|MAP_PRIVATE)) == (MAP_SHARED|MAP_PRIVATE))
246 		return EINVAL;
247 	if ((flags & (MAP_FIXED|__MAP_NOREPLACE)) == __MAP_NOREPLACE)
248 		return EINVAL;
249 	if (flags & MAP_STACK) {
250 		if ((flags & (MAP_ANON|MAP_PRIVATE)) != (MAP_ANON|MAP_PRIVATE))
251 			return EINVAL;
252 		if (flags & ~(MAP_STACK|MAP_FIXED|MAP_ANON|MAP_PRIVATE))
253 			return EINVAL;
254 		if (pos != 0)
255 			return EINVAL;
256 		if ((prot & (PROT_READ|PROT_WRITE)) != (PROT_READ|PROT_WRITE))
257 			return EINVAL;
258 	}
259 	if (size == 0)
260 		return EINVAL;
261 
262 	error = pledge_protexec(p, prot);
263 	if (error)
264 		return error;
265 
266 	/* align file position and save offset.  adjust size. */
267 	ALIGN_ADDR(pos, size, pageoff);
268 
269 	/* now check (MAP_FIXED) or get (!MAP_FIXED) the "addr" */
270 	if (flags & MAP_FIXED) {
271 		/* adjust address by the same amount as we did the offset */
272 		addr -= pageoff;
273 		if (addr & PAGE_MASK)
274 			return EINVAL;		/* not page aligned */
275 
276 		if (addr > SIZE_MAX - size)
277 			return EINVAL;		/* no wrapping! */
278 		if (VM_MAXUSER_ADDRESS > 0 &&
279 		    (addr + size) > VM_MAXUSER_ADDRESS)
280 			return EINVAL;
281 		if (vm_min_address > 0 && addr < vm_min_address)
282 			return EINVAL;
283 	}
284 
285 	/* check for file mappings (i.e. not anonymous) and verify file. */
286 	if ((flags & MAP_ANON) == 0) {
287 		KERNEL_LOCK();
288 		if ((fp = fd_getfile(fdp, fd)) == NULL) {
289 			error = EBADF;
290 			goto out;
291 		}
292 
293 		if (fp->f_type != DTYPE_VNODE) {
294 			error = ENODEV;		/* only mmap vnodes! */
295 			goto out;
296 		}
297 		vp = (struct vnode *)fp->f_data;	/* convert to vnode */
298 
299 		if (vp->v_type != VREG && vp->v_type != VCHR &&
300 		    vp->v_type != VBLK) {
301 			error = ENODEV; /* only REG/CHR/BLK support mmap */
302 			goto out;
303 		}
304 
305 		if (vp->v_type == VREG && (pos + size) < pos) {
306 			error = EINVAL;		/* no offset wrapping */
307 			goto out;
308 		}
309 
310 		/* special case: catch SunOS style /dev/zero */
311 		if (vp->v_type == VCHR && iszerodev(vp->v_rdev)) {
312 			flags |= MAP_ANON;
313 			FRELE(fp, p);
314 			fp = NULL;
315 			KERNEL_UNLOCK();
316 			goto is_anon;
317 		}
318 
319 		/*
320 		 * Old programs may not select a specific sharing type, so
321 		 * default to an appropriate one.
322 		 */
323 		if ((flags & (MAP_SHARED|MAP_PRIVATE)) == 0) {
324 #if defined(DEBUG)
325 			printf("WARNING: defaulted mmap() share type to"
326 			    " %s (pid %d comm %s)\n",
327 			    vp->v_type == VCHR ? "MAP_SHARED" : "MAP_PRIVATE",
328 			    p->p_p->ps_pid, p->p_p->ps_comm);
329 #endif
330 			if (vp->v_type == VCHR)
331 				flags |= MAP_SHARED;	/* for a device */
332 			else
333 				flags |= MAP_PRIVATE;	/* for a file */
334 		}
335 
336 		/*
337 		 * MAP_PRIVATE device mappings don't make sense (and aren't
338 		 * supported anyway).  However, some programs rely on this,
339 		 * so just change it to MAP_SHARED.
340 		 */
341 		if (vp->v_type == VCHR && (flags & MAP_PRIVATE) != 0) {
342 			flags = (flags & ~MAP_PRIVATE) | MAP_SHARED;
343 		}
344 
345 		/* now check protection */
346 		maxprot = PROT_EXEC;
347 
348 		/* check read access */
349 		if (fp->f_flag & FREAD)
350 			maxprot |= PROT_READ;
351 		else if (prot & PROT_READ) {
352 			error = EACCES;
353 			goto out;
354 		}
355 
356 		/* check write access, shared case first */
357 		if (flags & MAP_SHARED) {
358 			/*
359 			 * if the file is writable, only add PROT_WRITE to
360 			 * maxprot if the file is not immutable, append-only.
361 			 * otherwise, if we have asked for PROT_WRITE, return
362 			 * EPERM.
363 			 */
364 			if (fp->f_flag & FWRITE) {
365 				error = VOP_GETATTR(vp, &va, p->p_ucred, p);
366 				if (error)
367 					goto out;
368 				if ((va.va_flags & (IMMUTABLE|APPEND)) == 0)
369 					maxprot |= PROT_WRITE;
370 				else if (prot & PROT_WRITE) {
371 					error = EPERM;
372 					goto out;
373 				}
374 			} else if (prot & PROT_WRITE) {
375 				error = EACCES;
376 				goto out;
377 			}
378 		} else {
379 			/* MAP_PRIVATE mappings can always write to */
380 			maxprot |= PROT_WRITE;
381 		}
382 		if ((flags & __MAP_NOFAULT) != 0 ||
383 		    ((flags & MAP_PRIVATE) != 0 && (prot & PROT_WRITE) != 0)) {
384 			limit = lim_cur(RLIMIT_DATA);
385 			if (limit < size ||
386 			    limit - size < ptoa(p->p_vmspace->vm_dused)) {
387 				error = ENOMEM;
388 				goto out;
389 			}
390 		}
391 		error = uvm_mmapfile(&p->p_vmspace->vm_map, &addr, size, prot,
392 		    maxprot, flags, vp, pos, lim_cur(RLIMIT_MEMLOCK), p);
393 		FRELE(fp, p);
394 		KERNEL_UNLOCK();
395 	} else {		/* MAP_ANON case */
396 		if (fd != -1)
397 			return EINVAL;
398 
399 is_anon:	/* label for SunOS style /dev/zero */
400 
401 		/* __MAP_NOFAULT only makes sense with a backing object */
402 		if ((flags & __MAP_NOFAULT) != 0)
403 			return EINVAL;
404 
405 		if (prot != PROT_NONE || (flags & MAP_SHARED)) {
406 			limit = lim_cur(RLIMIT_DATA);
407 			if (limit < size ||
408 			    limit - size < ptoa(p->p_vmspace->vm_dused)) {
409 				return ENOMEM;
410 			}
411 		}
412 
413 		/*
414 		 * We've been treating (MAP_SHARED|MAP_PRIVATE) == 0 as
415 		 * MAP_PRIVATE, so make that clear.
416 		 */
417 		if ((flags & MAP_SHARED) == 0)
418 			flags |= MAP_PRIVATE;
419 
420 		maxprot = PROT_MASK;
421 		error = uvm_mmapanon(&p->p_vmspace->vm_map, &addr, size, prot,
422 		    maxprot, flags, lim_cur(RLIMIT_MEMLOCK), p);
423 	}
424 
425 	if (error == 0)
426 		/* remember to add offset */
427 		*retval = (register_t)(addr + pageoff);
428 
429 	return error;
430 
431 out:
432 	KERNEL_UNLOCK();
433 	if (fp)
434 		FRELE(fp, p);
435 	return error;
436 }
437 
438 /*
439  * sys_msync: the msync system call (a front-end for flush)
440  */
441 
442 int
443 sys_msync(struct proc *p, void *v, register_t *retval)
444 {
445 	struct sys_msync_args /* {
446 		syscallarg(void *) addr;
447 		syscallarg(size_t) len;
448 		syscallarg(int) flags;
449 	} */ *uap = v;
450 	vaddr_t addr;
451 	vsize_t size, pageoff;
452 	int flags, uvmflags;
453 
454 	/* extract syscall args from the uap */
455 	addr = (vaddr_t)SCARG(uap, addr);
456 	size = (vsize_t)SCARG(uap, len);
457 	flags = SCARG(uap, flags);
458 
459 	/* sanity check flags */
460 	if ((flags & ~(MS_ASYNC | MS_SYNC | MS_INVALIDATE)) != 0 ||
461 			(flags & (MS_ASYNC | MS_SYNC | MS_INVALIDATE)) == 0 ||
462 			(flags & (MS_ASYNC | MS_SYNC)) == (MS_ASYNC | MS_SYNC))
463 		return EINVAL;
464 	if ((flags & (MS_ASYNC | MS_SYNC)) == 0)
465 		flags |= MS_SYNC;
466 
467 	/* align the address to a page boundary, and adjust the size accordingly */
468 	ALIGN_ADDR(addr, size, pageoff);
469 	if (addr > SIZE_MAX - size)
470 		return EINVAL;		/* disallow wrap-around. */
471 
472 	/* translate MS_ flags into PGO_ flags */
473 	uvmflags = PGO_CLEANIT;
474 	if (flags & MS_INVALIDATE)
475 		uvmflags |= PGO_FREE;
476 	if (flags & MS_SYNC)
477 		uvmflags |= PGO_SYNCIO;
478 	else
479 		uvmflags |= PGO_SYNCIO;	 /* XXXCDC: force sync for now! */
480 
481 	return uvm_map_clean(&p->p_vmspace->vm_map, addr, addr+size, uvmflags);
482 }
483 
484 /*
485  * sys_munmap: unmap a users memory
486  */
487 int
488 sys_munmap(struct proc *p, void *v, register_t *retval)
489 {
490 	struct sys_munmap_args /* {
491 		syscallarg(void *) addr;
492 		syscallarg(size_t) len;
493 	} */ *uap = v;
494 	vaddr_t addr;
495 	vsize_t size, pageoff;
496 	vm_map_t map;
497 	vaddr_t vm_min_address = VM_MIN_ADDRESS;
498 	struct uvm_map_deadq dead_entries;
499 
500 	/* get syscall args... */
501 	addr = (vaddr_t) SCARG(uap, addr);
502 	size = (vsize_t) SCARG(uap, len);
503 
504 	/* align address to a page boundary, and adjust size accordingly */
505 	ALIGN_ADDR(addr, size, pageoff);
506 
507 	/*
508 	 * Check for illegal addresses.  Watch out for address wrap...
509 	 * Note that VM_*_ADDRESS are not constants due to casts (argh).
510 	 */
511 	if (addr > SIZE_MAX - size)
512 		return EINVAL;
513 	if (VM_MAXUSER_ADDRESS > 0 && addr + size > VM_MAXUSER_ADDRESS)
514 		return EINVAL;
515 	if (vm_min_address > 0 && addr < vm_min_address)
516 		return EINVAL;
517 	map = &p->p_vmspace->vm_map;
518 
519 
520 	vm_map_lock(map);	/* lock map so we can checkprot */
521 
522 	/*
523 	 * interesting system call semantic: make sure entire range is
524 	 * allocated before allowing an unmap.
525 	 */
526 	if (!uvm_map_checkprot(map, addr, addr + size, PROT_NONE)) {
527 		vm_map_unlock(map);
528 		return EINVAL;
529 	}
530 
531 	TAILQ_INIT(&dead_entries);
532 	if (uvm_unmap_remove(map, addr, addr + size, &dead_entries,
533 	    FALSE, TRUE, TRUE) != 0) {
534 		vm_map_unlock(map);
535 		return EPERM;	/* immutable entries found */
536 	}
537 	vm_map_unlock(map);	/* and unlock */
538 
539 	uvm_unmap_detach(&dead_entries, 0);
540 
541 	return 0;
542 }
543 
544 /*
545  * sys_mprotect: the mprotect system call
546  */
547 int
548 sys_mprotect(struct proc *p, void *v, register_t *retval)
549 {
550 	struct sys_mprotect_args /* {
551 		syscallarg(void *) addr;
552 		syscallarg(size_t) len;
553 		syscallarg(int) prot;
554 	} */ *uap = v;
555 	vaddr_t addr;
556 	vsize_t size, pageoff;
557 	vm_prot_t prot;
558 	int error;
559 
560 	/*
561 	 * extract syscall args from uap
562 	 */
563 
564 	addr = (vaddr_t)SCARG(uap, addr);
565 	size = (vsize_t)SCARG(uap, len);
566 	prot = SCARG(uap, prot);
567 
568 	if ((prot & PROT_MASK) != prot)
569 		return EINVAL;
570 	if ((prot & (PROT_WRITE | PROT_EXEC)) == (PROT_WRITE | PROT_EXEC) &&
571 	    (error = uvm_wxcheck(p, "mprotect")))
572 		return error;
573 
574 	error = pledge_protexec(p, prot);
575 	if (error)
576 		return error;
577 
578 	/*
579 	 * align the address to a page boundary, and adjust the size accordingly
580 	 */
581 	ALIGN_ADDR(addr, size, pageoff);
582 	if (addr > SIZE_MAX - size)
583 		return EINVAL;		/* disallow wrap-around. */
584 
585 	return (uvm_map_protect(&p->p_vmspace->vm_map, addr, addr+size,
586 	    prot, 0, FALSE, TRUE));
587 }
588 
589 /*
590  * sys_msyscall: the msyscall system call
591  */
592 int
593 sys_msyscall(struct proc *p, void *v, register_t *retval)
594 {
595 	struct sys_msyscall_args /* {
596 		syscallarg(void *) addr;
597 		syscallarg(size_t) len;
598 	} */ *uap = v;
599 	vaddr_t addr;
600 	vsize_t size, pageoff;
601 
602 	addr = (vaddr_t)SCARG(uap, addr);
603 	size = (vsize_t)SCARG(uap, len);
604 
605 	/*
606 	 * align the address to a page boundary, and adjust the size accordingly
607 	 */
608 	ALIGN_ADDR(addr, size, pageoff);
609 	if (addr > SIZE_MAX - size)
610 		return EINVAL;		/* disallow wrap-around. */
611 
612 	return uvm_map_syscall(&p->p_vmspace->vm_map, addr, addr+size);
613 }
614 
615 /*
616  * sys_pinsyscall
617  */
618 int
619 sys_pinsyscall(struct proc *p, void *v, register_t *retval)
620 {
621 	return (0);
622 }
623 
624 /*
625  * sys_pinsyscalls.  The caller is required to normalize base,len
626  * to the minimum .text region, and adjust pintable offsets relative
627  * to that base.
628  */
629 int
630 sys_pinsyscalls(struct proc *p, void *v, register_t *retval)
631 {
632 	struct sys_pinsyscalls_args /* {
633 		syscallarg(void *) base;
634 		syscallarg(size_t) len;
635 		syscallarg(u_int *) pins;
636 		syscallarg(int) npins;
637 	} */ *uap = v;
638 	struct process *pr = p->p_p;
639 	int npins, error = 0, i;
640 	vaddr_t base;
641 	size_t len;
642 	u_int *pins;
643 
644 	if (pr->ps_libcpin.pn_start ||
645 	    (pr->ps_vmspace->vm_map.flags & VM_MAP_PINSYSCALL_ONCE))
646 		return (EPERM);
647 	base = (vaddr_t)SCARG(uap, base);
648 	len = (vsize_t)SCARG(uap, len);
649 	if (base > SIZE_MAX - len)
650 		return (EINVAL);	/* disallow wrap-around. */
651 
652 	/* XXX MP unlock */
653 
654 	npins = SCARG(uap, npins);
655 	if (npins < 1 || npins > SYS_MAXSYSCALL)
656 		return (E2BIG);
657 	pins = malloc(npins * sizeof(u_int), M_PINSYSCALL, M_WAITOK|M_ZERO);
658 	if (pins == NULL)
659 		return (ENOMEM);
660 	error = copyin(SCARG(uap, pins), pins, npins * sizeof(u_int));
661 	if (error)
662 		goto err;
663 
664 	/* Range-check pintable offsets */
665 	for (i = 0; i < npins; i++) {
666 		if (pins[i] == (u_int)-1 || pins[i] == 0)
667 			continue;
668 		if (pins[i] > SCARG(uap, len)) {
669 			error = ERANGE;
670 			break;
671 		}
672 	}
673 	if (error) {
674 err:
675 		free(pins, M_PINSYSCALL, npins * sizeof(u_int));
676 		return (error);
677 	}
678 	pr->ps_libcpin.pn_start = base;
679 	pr->ps_libcpin.pn_end = base + len;
680 	pr->ps_libcpin.pn_pins = pins;
681 	pr->ps_libcpin.pn_npins = npins;
682 	pr->ps_flags |= PS_LIBCPIN;
683 	return (0);
684 }
685 
686 /*
687  * sys_mimmutable: the mimmutable system call
688  */
689 int
690 sys_mimmutable(struct proc *p, void *v, register_t *retval)
691 {
692 	struct sys_mimmutable_args /* {
693 		immutablearg(void *) addr;
694 		immutablearg(size_t) len;
695 	} */ *uap = v;
696 	vaddr_t addr;
697 	vsize_t size, pageoff;
698 
699 	addr = (vaddr_t)SCARG(uap, addr);
700 	size = (vsize_t)SCARG(uap, len);
701 
702 	/*
703 	 * align the address to a page boundary, and adjust the size accordingly
704 	 */
705 	ALIGN_ADDR(addr, size, pageoff);
706 	if (addr > SIZE_MAX - size)
707 		return EINVAL;		/* disallow wrap-around. */
708 
709 	return uvm_map_immutable(&p->p_vmspace->vm_map, addr, addr+size, 1);
710 }
711 
712 /*
713  * sys_minherit: the minherit system call
714  */
715 int
716 sys_minherit(struct proc *p, void *v, register_t *retval)
717 {
718 	struct sys_minherit_args /* {
719 		syscallarg(void *) addr;
720 		syscallarg(size_t) len;
721 		syscallarg(int) inherit;
722 	} */ *uap = v;
723 	vaddr_t addr;
724 	vsize_t size, pageoff;
725 	vm_inherit_t inherit;
726 
727 	addr = (vaddr_t)SCARG(uap, addr);
728 	size = (vsize_t)SCARG(uap, len);
729 	inherit = SCARG(uap, inherit);
730 
731 	/*
732 	 * align the address to a page boundary, and adjust the size accordingly
733 	 */
734 	ALIGN_ADDR(addr, size, pageoff);
735 	if (addr > SIZE_MAX - size)
736 		return EINVAL;		/* disallow wrap-around. */
737 
738 	return (uvm_map_inherit(&p->p_vmspace->vm_map, addr, addr+size,
739 	    inherit));
740 }
741 
742 /*
743  * sys_madvise: give advice about memory usage.
744  */
745 int
746 sys_madvise(struct proc *p, void *v, register_t *retval)
747 {
748 	struct sys_madvise_args /* {
749 		syscallarg(void *) addr;
750 		syscallarg(size_t) len;
751 		syscallarg(int) behav;
752 	} */ *uap = v;
753 	vaddr_t addr;
754 	vsize_t size, pageoff;
755 	int advice, error;
756 
757 	addr = (vaddr_t)SCARG(uap, addr);
758 	size = (vsize_t)SCARG(uap, len);
759 	advice = SCARG(uap, behav);
760 
761 	/*
762 	 * align the address to a page boundary, and adjust the size accordingly
763 	 */
764 	ALIGN_ADDR(addr, size, pageoff);
765 	if (addr > SIZE_MAX - size)
766 		return EINVAL;		/* disallow wrap-around. */
767 
768 	switch (advice) {
769 	case MADV_NORMAL:
770 	case MADV_RANDOM:
771 	case MADV_SEQUENTIAL:
772 		error = uvm_map_advice(&p->p_vmspace->vm_map, addr,
773 		    addr + size, advice);
774 		break;
775 
776 	case MADV_WILLNEED:
777 		/*
778 		 * Activate all these pages, pre-faulting them in if
779 		 * necessary.
780 		 */
781 		/*
782 		 * XXX IMPLEMENT ME.
783 		 * Should invent a "weak" mode for uvm_fault()
784 		 * which would only do the PGO_LOCKED pgo_get().
785 		 */
786 		return 0;
787 
788 	case MADV_DONTNEED:
789 		/*
790 		 * Deactivate all these pages.  We don't need them
791 		 * any more.  We don't, however, toss the data in
792 		 * the pages.
793 		 */
794 		error = uvm_map_clean(&p->p_vmspace->vm_map, addr, addr + size,
795 		    PGO_DEACTIVATE);
796 		break;
797 
798 	case MADV_FREE:
799 		/*
800 		 * These pages contain no valid data, and may be
801 		 * garbage-collected.  Toss all resources, including
802 		 * any swap space in use.
803 		 */
804 		error = uvm_map_clean(&p->p_vmspace->vm_map, addr, addr + size,
805 		    PGO_FREE);
806 		break;
807 
808 	case MADV_SPACEAVAIL:
809 		/*
810 		 * XXXMRG What is this?  I think it's:
811 		 *
812 		 *	Ensure that we have allocated backing-store
813 		 *	for these pages.
814 		 *
815 		 * This is going to require changes to the page daemon,
816 		 * as it will free swap space allocated to pages in core.
817 		 * There's also what to do for device/file/anonymous memory.
818 		 */
819 		return EINVAL;
820 
821 	default:
822 		return EINVAL;
823 	}
824 
825 	return error;
826 }
827 
828 /*
829  * sys_mlock: memory lock
830  */
831 
832 int
833 sys_mlock(struct proc *p, void *v, register_t *retval)
834 {
835 	struct sys_mlock_args /* {
836 		syscallarg(const void *) addr;
837 		syscallarg(size_t) len;
838 	} */ *uap = v;
839 	vaddr_t addr;
840 	vsize_t size, pageoff;
841 	int error;
842 
843 	/* extract syscall args from uap */
844 	addr = (vaddr_t)SCARG(uap, addr);
845 	size = (vsize_t)SCARG(uap, len);
846 
847 	/* align address to a page boundary and adjust size accordingly */
848 	ALIGN_ADDR(addr, size, pageoff);
849 	if (addr > SIZE_MAX - size)
850 		return EINVAL;		/* disallow wrap-around. */
851 
852 	if (atop(size) + uvmexp.wired > uvmexp.wiredmax)
853 		return EAGAIN;
854 
855 #ifdef pmap_wired_count
856 	if (size + ptoa(pmap_wired_count(vm_map_pmap(&p->p_vmspace->vm_map))) >
857 			lim_cur(RLIMIT_MEMLOCK))
858 		return EAGAIN;
859 #else
860 	if ((error = suser(p)) != 0)
861 		return error;
862 #endif
863 
864 	error = uvm_map_pageable(&p->p_vmspace->vm_map, addr, addr+size, FALSE,
865 	    0);
866 	return error == 0 ? 0 : ENOMEM;
867 }
868 
869 /*
870  * sys_munlock: unlock wired pages
871  */
872 
873 int
874 sys_munlock(struct proc *p, void *v, register_t *retval)
875 {
876 	struct sys_munlock_args /* {
877 		syscallarg(const void *) addr;
878 		syscallarg(size_t) len;
879 	} */ *uap = v;
880 	vaddr_t addr;
881 	vsize_t size, pageoff;
882 	int error;
883 
884 	/* extract syscall args from uap */
885 	addr = (vaddr_t)SCARG(uap, addr);
886 	size = (vsize_t)SCARG(uap, len);
887 
888 	/* align address to a page boundary, and adjust size accordingly */
889 	ALIGN_ADDR(addr, size, pageoff);
890 	if (addr > SIZE_MAX - size)
891 		return EINVAL;		/* disallow wrap-around. */
892 
893 #ifndef pmap_wired_count
894 	if ((error = suser(p)) != 0)
895 		return error;
896 #endif
897 
898 	error = uvm_map_pageable(&p->p_vmspace->vm_map, addr, addr+size, TRUE,
899 	    0);
900 	return error == 0 ? 0 : ENOMEM;
901 }
902 
903 /*
904  * sys_mlockall: lock all pages mapped into an address space.
905  */
906 int
907 sys_mlockall(struct proc *p, void *v, register_t *retval)
908 {
909 	struct sys_mlockall_args /* {
910 		syscallarg(int) flags;
911 	} */ *uap = v;
912 	int error, flags;
913 
914 	flags = SCARG(uap, flags);
915 
916 	if (flags == 0 ||
917 	    (flags & ~(MCL_CURRENT|MCL_FUTURE)) != 0)
918 		return EINVAL;
919 
920 #ifndef pmap_wired_count
921 	if ((error = suser(p)) != 0)
922 		return error;
923 #endif
924 
925 	error = uvm_map_pageable_all(&p->p_vmspace->vm_map, flags,
926 	    lim_cur(RLIMIT_MEMLOCK));
927 	if (error != 0 && error != ENOMEM)
928 		return EAGAIN;
929 	return error;
930 }
931 
932 /*
933  * sys_munlockall: unlock all pages mapped into an address space.
934  */
935 int
936 sys_munlockall(struct proc *p, void *v, register_t *retval)
937 {
938 
939 	(void) uvm_map_pageable_all(&p->p_vmspace->vm_map, 0, 0);
940 	return 0;
941 }
942 
943 /*
944  * common code for mmapanon and mmapfile to lock a mmaping
945  */
946 int
947 uvm_mmaplock(vm_map_t map, vaddr_t *addr, vsize_t size, vm_prot_t prot,
948     vsize_t locklimit)
949 {
950 	int error;
951 
952 	/*
953 	 * POSIX 1003.1b -- if our address space was configured
954 	 * to lock all future mappings, wire the one we just made.
955 	 */
956 	if (prot == PROT_NONE) {
957 		/*
958 		 * No more work to do in this case.
959 		 */
960 		return 0;
961 	}
962 
963 	vm_map_lock(map);
964 	if (map->flags & VM_MAP_WIREFUTURE) {
965 		KERNEL_LOCK();
966 		if ((atop(size) + uvmexp.wired) > uvmexp.wiredmax
967 #ifdef pmap_wired_count
968 		    || (locklimit != 0 && (size +
969 			 ptoa(pmap_wired_count(vm_map_pmap(map)))) >
970 			locklimit)
971 #endif
972 		) {
973 			error = ENOMEM;
974 			vm_map_unlock(map);
975 			/* unmap the region! */
976 			uvm_unmap(map, *addr, *addr + size);
977 			KERNEL_UNLOCK();
978 			return error;
979 		}
980 		/*
981 		 * uvm_map_pageable() always returns the map
982 		 * unlocked.
983 		 */
984 		error = uvm_map_pageable(map, *addr, *addr + size,
985 		    FALSE, UVM_LK_ENTER);
986 		if (error != 0) {
987 			/* unmap the region! */
988 			uvm_unmap(map, *addr, *addr + size);
989 			KERNEL_UNLOCK();
990 			return error;
991 		}
992 		KERNEL_UNLOCK();
993 		return 0;
994 	}
995 	vm_map_unlock(map);
996 	return 0;
997 }
998 
999 /*
1000  * uvm_mmapanon: internal version of mmap for anons
1001  *
1002  * - used by sys_mmap
1003  */
1004 int
1005 uvm_mmapanon(vm_map_t map, vaddr_t *addr, vsize_t size, vm_prot_t prot,
1006     vm_prot_t maxprot, int flags, vsize_t locklimit, struct proc *p)
1007 {
1008 	int error;
1009 	int advice = MADV_NORMAL;
1010 	unsigned int uvmflag = 0;
1011 	vsize_t align = 0;	/* userland page size */
1012 
1013 	/*
1014 	 * for non-fixed mappings, round off the suggested address.
1015 	 * for fixed mappings, check alignment and zap old mappings.
1016 	 */
1017 	if ((flags & MAP_FIXED) == 0) {
1018 		*addr = round_page(*addr);	/* round */
1019 	} else {
1020 		if (*addr & PAGE_MASK)
1021 			return EINVAL;
1022 
1023 		uvmflag |= UVM_FLAG_FIXED;
1024 		if ((flags & __MAP_NOREPLACE) == 0)
1025 			uvmflag |= UVM_FLAG_UNMAP;
1026 	}
1027 
1028 	if ((flags & MAP_FIXED) == 0 && size >= __LDPGSZ)
1029 		align = __LDPGSZ;
1030 	if ((flags & MAP_SHARED) == 0)
1031 		/* XXX: defer amap create */
1032 		uvmflag |= UVM_FLAG_COPYONW;
1033 	else
1034 		/* shared: create amap now */
1035 		uvmflag |= UVM_FLAG_OVERLAY;
1036 	if (flags & MAP_STACK)
1037 		uvmflag |= UVM_FLAG_STACK;
1038 	if (flags & MAP_CONCEAL)
1039 		uvmflag |= UVM_FLAG_CONCEAL;
1040 
1041 	/* set up mapping flags */
1042 	uvmflag = UVM_MAPFLAG(prot, maxprot,
1043 	    (flags & MAP_SHARED) ? MAP_INHERIT_SHARE : MAP_INHERIT_COPY,
1044 	    advice, uvmflag);
1045 
1046 	error = uvm_mapanon(map, addr, size, align, uvmflag);
1047 
1048 	if (error == 0)
1049 		error = uvm_mmaplock(map, addr, size, prot, locklimit);
1050 	return error;
1051 }
1052 
1053 /*
1054  * uvm_mmapfile: internal version of mmap for non-anons
1055  *
1056  * - used by sys_mmap
1057  * - caller must page-align the file offset
1058  */
1059 int
1060 uvm_mmapfile(vm_map_t map, vaddr_t *addr, vsize_t size, vm_prot_t prot,
1061     vm_prot_t maxprot, int flags, struct vnode *vp, voff_t foff,
1062     vsize_t locklimit, struct proc *p)
1063 {
1064 	struct uvm_object *uobj;
1065 	int error;
1066 	int advice = MADV_NORMAL;
1067 	unsigned int uvmflag = 0;
1068 	vsize_t align = 0;	/* userland page size */
1069 
1070 	/*
1071 	 * for non-fixed mappings, round off the suggested address.
1072 	 * for fixed mappings, check alignment and zap old mappings.
1073 	 */
1074 	if ((flags & MAP_FIXED) == 0) {
1075 		*addr = round_page(*addr);	/* round */
1076 	} else {
1077 		if (*addr & PAGE_MASK)
1078 			return EINVAL;
1079 
1080 		uvmflag |= UVM_FLAG_FIXED;
1081 		if ((flags & __MAP_NOREPLACE) == 0)
1082 			uvmflag |= UVM_FLAG_UNMAP;
1083 	}
1084 
1085 	/*
1086 	 * attach to underlying vm object.
1087 	 */
1088 	if (vp->v_type != VCHR) {
1089 		uobj = uvn_attach(vp, (flags & MAP_SHARED) ?
1090 		   maxprot : (maxprot & ~PROT_WRITE));
1091 
1092 		/*
1093 		 * XXXCDC: hack from old code
1094 		 * don't allow vnodes which have been mapped
1095 		 * shared-writeable to persist [forces them to be
1096 		 * flushed out when last reference goes].
1097 		 * XXXCDC: interesting side effect: avoids a bug.
1098 		 * note that in WRITE [ufs_readwrite.c] that we
1099 		 * allocate buffer, uncache, and then do the write.
1100 		 * the problem with this is that if the uncache causes
1101 		 * VM data to be flushed to the same area of the file
1102 		 * we are writing to... in that case we've got the
1103 		 * buffer locked and our process goes to sleep forever.
1104 		 *
1105 		 * XXXCDC: checking maxprot protects us from the
1106 		 * "persistbug" program but this is not a long term
1107 		 * solution.
1108 		 *
1109 		 * XXXCDC: we don't bother calling uncache with the vp
1110 		 * VOP_LOCKed since we know that we are already
1111 		 * holding a valid reference to the uvn (from the
1112 		 * uvn_attach above), and thus it is impossible for
1113 		 * the uncache to kill the uvn and trigger I/O.
1114 		 */
1115 		if (flags & MAP_SHARED) {
1116 			if ((prot & PROT_WRITE) ||
1117 			    (maxprot & PROT_WRITE)) {
1118 				uvm_vnp_uncache(vp);
1119 			}
1120 		}
1121 	} else {
1122 		uobj = udv_attach(vp->v_rdev,
1123 		    (flags & MAP_SHARED) ? maxprot :
1124 		    (maxprot & ~PROT_WRITE), foff, size);
1125 		/*
1126 		 * XXX Some devices don't like to be mapped with
1127 		 * XXX PROT_EXEC, but we don't really have a
1128 		 * XXX better way of handling this, right now
1129 		 */
1130 		if (uobj == NULL && (prot & PROT_EXEC) == 0) {
1131 			maxprot &= ~PROT_EXEC;
1132 			uobj = udv_attach(vp->v_rdev,
1133 			    (flags & MAP_SHARED) ? maxprot :
1134 			    (maxprot & ~PROT_WRITE), foff, size);
1135 		}
1136 		advice = MADV_RANDOM;
1137 	}
1138 
1139 	if (uobj == NULL)
1140 		return vp->v_type == VREG ? ENOMEM : EINVAL;
1141 
1142 	if ((flags & MAP_SHARED) == 0)
1143 		uvmflag |= UVM_FLAG_COPYONW;
1144 	if (flags & __MAP_NOFAULT)
1145 		uvmflag |= (UVM_FLAG_NOFAULT | UVM_FLAG_OVERLAY);
1146 	if (flags & MAP_STACK)
1147 		uvmflag |= UVM_FLAG_STACK;
1148 	if (flags & MAP_CONCEAL)
1149 		uvmflag |= UVM_FLAG_CONCEAL;
1150 
1151 	/* set up mapping flags */
1152 	uvmflag = UVM_MAPFLAG(prot, maxprot,
1153 	    (flags & MAP_SHARED) ? MAP_INHERIT_SHARE : MAP_INHERIT_COPY,
1154 	    advice, uvmflag);
1155 
1156 	error = uvm_map(map, addr, size, uobj, foff, align, uvmflag);
1157 
1158 	if (error == 0)
1159 		return uvm_mmaplock(map, addr, size, prot, locklimit);
1160 
1161 	/* errors: first detach from the uobj, if any.  */
1162 	if (uobj)
1163 		uobj->pgops->pgo_detach(uobj);
1164 
1165 	return error;
1166 }
1167 
1168 int
1169 sys_kbind(struct proc *p, void *v, register_t *retval)
1170 {
1171 	struct sys_kbind_args /* {
1172 		syscallarg(const struct __kbind *) param;
1173 		syscallarg(size_t) psize;
1174 		syscallarg(uint64_t) proc_cookie;
1175 	} */ *uap = v;
1176 	const struct __kbind *paramp;
1177 	union {
1178 		struct __kbind uk[KBIND_BLOCK_MAX];
1179 		char upad[KBIND_BLOCK_MAX * sizeof(*paramp) + KBIND_DATA_MAX];
1180 	} param;
1181 	struct uvm_map_deadq dead_entries;
1182 	struct process *pr = p->p_p;
1183 	const char *data;
1184 	vaddr_t baseva, last_baseva, endva, pageoffset, kva;
1185 	size_t psize, s;
1186 	u_long pc;
1187 	int count, i, extra;
1188 	int error, sigill = 0;
1189 
1190 	/*
1191 	 * extract syscall args from uap
1192 	 */
1193 	paramp = SCARG(uap, param);
1194 	psize = SCARG(uap, psize);
1195 
1196 	/*
1197 	 * If paramp is NULL and we're uninitialized, disable the syscall
1198 	 * for the process.  Raise SIGILL if paramp is NULL and we're
1199 	 * already initialized.
1200 	 *
1201 	 * If paramp is non-NULL and we're uninitialized, do initialization.
1202 	 * Otherwise, do security checks and raise SIGILL on failure.
1203 	 */
1204 	pc = PROC_PC(p);
1205 	mtx_enter(&pr->ps_mtx);
1206 	if (paramp == NULL) {
1207 		/* ld.so disables kbind() when lazy binding is disabled */
1208 		if (pr->ps_kbind_addr == 0)
1209 			pr->ps_kbind_addr = BOGO_PC;
1210 		/* pre-7.3 static binaries disable kbind */
1211 		/* XXX delete check in 2026 */
1212 		else if (pr->ps_kbind_addr != BOGO_PC)
1213 			sigill = 1;
1214 	} else if (pr->ps_kbind_addr == 0) {
1215 		pr->ps_kbind_addr = pc;
1216 		pr->ps_kbind_cookie = SCARG(uap, proc_cookie);
1217 	} else if (pc != pr->ps_kbind_addr || pc == BOGO_PC ||
1218 	    pr->ps_kbind_cookie != SCARG(uap, proc_cookie)) {
1219 		sigill = 1;
1220 	}
1221 	mtx_leave(&pr->ps_mtx);
1222 
1223 	/* Raise SIGILL if something is off. */
1224 	if (sigill) {
1225 		KERNEL_LOCK();
1226 		sigexit(p, SIGILL);
1227 		/* NOTREACHED */
1228 		KERNEL_UNLOCK();
1229 	}
1230 
1231 	/* We're done if we were disabling the syscall. */
1232 	if (paramp == NULL)
1233 		return 0;
1234 
1235 	if (psize < sizeof(struct __kbind) || psize > sizeof(param))
1236 		return EINVAL;
1237 	if ((error = copyin(paramp, &param, psize)))
1238 		return error;
1239 
1240 	/*
1241 	 * The param argument points to an array of __kbind structures
1242 	 * followed by the corresponding new data areas for them.  Verify
1243 	 * that the sizes in the __kbind structures add up to the total
1244 	 * size and find the start of the new area.
1245 	 */
1246 	paramp = &param.uk[0];
1247 	s = psize;
1248 	for (count = 0; s > 0 && count < KBIND_BLOCK_MAX; count++) {
1249 		if (s < sizeof(*paramp))
1250 			return EINVAL;
1251 		s -= sizeof(*paramp);
1252 
1253 		baseva = (vaddr_t)paramp[count].kb_addr;
1254 		endva = baseva + paramp[count].kb_size - 1;
1255 		if (paramp[count].kb_addr == NULL ||
1256 		    paramp[count].kb_size == 0 ||
1257 		    paramp[count].kb_size > KBIND_DATA_MAX ||
1258 		    baseva >= VM_MAXUSER_ADDRESS ||
1259 		    endva >= VM_MAXUSER_ADDRESS ||
1260 		    s < paramp[count].kb_size)
1261 			return EINVAL;
1262 
1263 		s -= paramp[count].kb_size;
1264 	}
1265 	if (s > 0)
1266 		return EINVAL;
1267 	data = (const char *)&paramp[count];
1268 
1269 	/* all looks good, so do the bindings */
1270 	last_baseva = VM_MAXUSER_ADDRESS;
1271 	kva = 0;
1272 	TAILQ_INIT(&dead_entries);
1273 	KERNEL_LOCK();
1274 	for (i = 0; i < count; i++) {
1275 		baseva = (vaddr_t)paramp[i].kb_addr;
1276 		s = paramp[i].kb_size;
1277 		pageoffset = baseva & PAGE_MASK;
1278 		baseva = trunc_page(baseva);
1279 
1280 		/* hppa at least runs PLT entries over page edge */
1281 		extra = (pageoffset + s) & PAGE_MASK;
1282 		if (extra > pageoffset)
1283 			extra = 0;
1284 		else
1285 			s -= extra;
1286 redo:
1287 		/* make sure the desired page is mapped into kernel_map */
1288 		if (baseva != last_baseva) {
1289 			if (kva != 0) {
1290 				vm_map_lock(kernel_map);
1291 				uvm_unmap_remove(kernel_map, kva,
1292 				    kva+PAGE_SIZE, &dead_entries,
1293 				    FALSE, TRUE, FALSE);	/* XXX */
1294 				vm_map_unlock(kernel_map);
1295 				kva = 0;
1296 			}
1297 			if ((error = uvm_map_extract(&p->p_vmspace->vm_map,
1298 			    baseva, PAGE_SIZE, &kva, UVM_EXTRACT_FIXPROT)))
1299 				break;
1300 			last_baseva = baseva;
1301 		}
1302 
1303 		/* do the update */
1304 		if ((error = kcopy(data, (char *)kva + pageoffset, s)))
1305 			break;
1306 		data += s;
1307 
1308 		if (extra > 0) {
1309 			baseva += PAGE_SIZE;
1310 			s = extra;
1311 			pageoffset = 0;
1312 			extra = 0;
1313 			goto redo;
1314 		}
1315 	}
1316 
1317 	if (kva != 0) {
1318 		vm_map_lock(kernel_map);
1319 		uvm_unmap_remove(kernel_map, kva, kva+PAGE_SIZE,
1320 		    &dead_entries, FALSE, TRUE, FALSE);		/* XXX */
1321 		vm_map_unlock(kernel_map);
1322 	}
1323 	uvm_unmap_detach(&dead_entries, AMAP_REFALL);
1324 	KERNEL_UNLOCK();
1325 
1326 	return error;
1327 }
1328